Joint or separate operation of control valves for two fluid motors



Feb. 25, 1947.

1'. BROWN JOINT OR SEPARATE OPERATION OF CONTROL VALVES FOR TWO FLUIDMOTORS Filed Feb. 13 1943 FIG. I

5 Sheets-Sheet 1 invzumn.

Feb. 25, 1947. 1'. BROWN 2,415,373

J JOINT OR SEPARATE OPERATI'ONOF CONTROL VALVES FOR TWO FLUID MOTORS 5Sheets-Sheet 2 Filed Feb. 1, 1943' nvmvron' THEOPHIITUS BROWN I A v Feb.25, 1947. T. BROWN 2,416,373

. JOINT OR SEPARATE OPERATION OF CONTROL VALVES FOR TWO FLUID MOTORSFiled Feb. 1, 1943 5 Sheets-Sheet 3 FIG. 4

JUJVIIIIIA gas 2 3 7 7 L A 4 m T m m B r M. l.- L A 9 .(lv... T

INVENTOR. THEOPHILUS BROWN FeB. 25, 1947.

'r. BROWN 2,416,373 JOINT OR SEPARATE OPERATION OF CONTROL VALVES FORTWO FLUID MOTORSI I Filed Feb. 1, 1943 5 Sheets-Sheet IN V EN TOR.THEOPHILUS BROWN Feb. 25, 1947. T. BROWN 2,415,373

JOINT OR SEPARATE OPERATION OF CONTROL VALVES FOR TWO FLUID MOTORS FiledFeb. 1, 1943 5 Sheets-Sheet 5 uvyENrok THEOPHILUS a'RowN Patented 425,1941 oFncE JOINT OR SEPARATE OPERATION OF CON TBOL VALVES FOR TWO MOTORSTheophilus Brown, Moline, m, assignor to Deere J & Company, Moiine,111., a corporation of Illinois Application February 1,1943, Serial Nb.414,404

7 Claims. 1

The present invention relates generally to power lift mechanism foragricultural tractors I and the like, and more particularly to hydraulicmechanism including two separately operable ram units. The object andgeneral nature of the present invention is the provision of hydraulicmech-- anism including a pair of ram units with control means thereforso constructed and arranged that the ram units may be simultaneouslyoperated and controlled or operated and controlled separately orindividually. A further feature of this invention is the provision ofapair of ram units each having means for returning the'controlling valveto a neutral position after a given amount of extension of the ram unit,with a single control member shiftable from an intermediate position inwhich both ram units are controlled into either of two other positionsfor operating the ram units separately or individually, as desired.Specifically, it is a feature of this invention to provide suitablecontrol means associated with each ram unit and adapted, when the singlecontrol membe! is in a central position, to act through said member toreturn both valves to a neutral position, or to return only'the valve ofthe ram unit being operated. to neutral position automatically, the sameadjustment being employed, whether both of the ram units are controlledtogether or separately; A further feature of this invention is theprovision of hydraulic mechanism including a pair of ram units, eachhaving its own individual control, with means shiftable from one 2erally along the line 2-2 of Figure 1, showing one of the piston andcylinder or ram units and the associated-gear pump;

Figure 3 is a section taken generally along'theline 3-3 of Figure 1 andshowing the other piston and cylinder or ram unit and-its associatedpump;

I Figure 4' is an enlarged rear view, certain parts being shown insection, showing the two control valve'boxes and the associatedshiftable valve control lever associated therewith;

Figure 5 is a modified form of the present invention in which two ramunits are associated with a single source of fluid pressure such as apump, with optionally controlled means for 'operating the two ram unitseither separately or simultaneously; v

Figure 6 is a fragmentary top view of the shiftable valve controlhandle; and

Figure? is a diagrammatic view of the valve S mechanism Referring now tothe drawings, particularly I Figure 1, the reference numeral 1'indicates a ally outer ends of the axles 9. Secured to the laterallyinner end of each of the axle shafts 9 is a drive gear ll arranged inthe tractor to position, in which both controls are operated together,into another position in which the controls maybe operated individually.More speciflcally, it is a feature of 7 this invention to proconnectionwith a single source of power, such as a positive displacement pump,with a bleeder valve arranged in the system for diverting a quantity offluid when only one ram unit is extended, the bleeder valve beingadapted to be automatically closed whenboth ram units are operatedtogether, whereby the time of operation, whether both units together, oronly one, is the same in both cases'or substantially so.

These and other objects and advantages of the present invention willbeapparent to those skilled in the art after a consideration of thefollowing detailed description, taken in conjunction with theaccompanying-drawings, in which Figure 1 is a plan view of anagricultural tractor -vide a hydraulic arrangement of this kind inequipped with hydraulic apparatus of the present farm tractor which issupported on front wheels 2 and rear traction wheels 3 and whichcomprises a, motor. and a combined crank caseand supporting structure,indicated generally at 5, to

which arear axle housing 6 is bolted. The rear axle housing 6 includeslaterally directed housing section 1 and 8 in which drive axles 9 arejournaled. The wheels 3 are mounted on the laterbe driven bytransmission mechanism (not shown) that in turn is driven by the tractormotor 4. The rear portion of the combined crank case and supportingstructure 5 and the adjacent portions of the rear axle housing 6 are soconstructed that there is a space s between each gear I l and the sideof the associated housings.

. As best shown in Figure 2, a power lift housing, indicated in itsentirety by the reference numeral I5, is bolted to the rear face of therear axlehousing 6, and a lifting rockshaft I6 is.

unit, indicated in its entirety by the'reference 3 numeral 25, which isconnected to rock the shaft 16 for the purpose of raising or liftingimplement parts for performing other functions, as desired.

A second piston and cylinder or ram unit 26 is disposed at the otherside of the tractor. as best shown in Figures 1 and 3. A liftingrockshaft 26 is mounted in the left portion of the power lift housingi6, generally in axial alignment with the rockshaft It. An arm 29' issecured to the lifting rockshaft 28 and is connected by a link or pistonrod 3! to a piston 32 disposed in a cylinder 33 thatis bolted. to thefront side of the power lift housing l5, generally at the left side ofthe tractor, as shown in Figure 1, the piston 32 and cylinder 33constituting parts of the ram unit 26 above referred to. A passageway 34directs fluid under pressure into the cylinder 33 V ahead of the piston32.

1 According to the'principles of the present invention, each of the ramunits 25 and 26 is provided with its own source of pressure, such as agear pump of the positive displacement type. Generally, the gear pumpsare similar to the type of pump shown in the United States PatentNo.2,107,760, issued February 8, 1938, to E; McCormick et al.,-to whichreference may be had if desired. In the McCormick et a1. patent only onepump is shown, but, according to the present invention, two' pumps areemployed, both driven from the same shaft, as will now be described; Thepower take-ofi shaft of the tractor isindicated by the reference numeral4| and is connected with the tractor motor 4 through suitable gearing(not shown). Normally, the tractor mtor is operated at a substantiallyconstant speed by suitable governor mechanism and therefore the pump orpumps driven from the power take- .ofi shaft 4| are also operated atconstant speed,

and being positive displacement devices such pumps form a source offluid under pressure delivered at substantially constant volume andpressure per unit time.

Referring now. to Figure 2, the power take-oil shaft 4| is somewhatlonger than the corresponding part in the power lift mechanism shown-inthe above-mentioned E. McCormick et al. patent; Secured to the rear sideof thepowerlift housing I is a pair of substantially identical pumpcasings 42 and 43, each enclosing a pair of pump gears, there beingvonegear of each pair splined onto or otherwise connected tobe rotated bythe power take-oil shaft 4!. The pump gears in the tially in the samemanner as illustrated in the E.

McCormick et a]. patent, and a high pressure passage 46 is formed in thepump casing 42 and in the adjacent portions of the'power. lift housingl5. The upper end of the high pressure passage 48 communicates with avalve box 50a (Figure 4), and a similar high pressure passage 49 (Figure3) extends from the high pressure side of the pump gears 46 upwardlythrough the casing 43, through a portion of the casing 42 and intocooperating passages 49a in the power lift housin leading to a secondvalve box 561: (Figure 4).

.Wayne H. Worthington, except that in the present instance each valvebox 56a and 50b contains only'one controlling valve, rather than a pairof controlling valves as in the Worthington -patent. Since, as mentionedabove, the present invention is not especially concerned with theparticular details of the valves or their operating means,-only a briefdescription will be necessary. Referring now more particularly to Figurein which the valve mechanisms are illustrated diagrammatically, the highpressure passage 48 leading from the pump gears 45.communicatesat itsupper end with apassage 55 that leads upwardly and at its upper endcommunicates with a valve bore 56 formed in the casing of the valve box50a. A valve 51 is movable vertically within the valve bore 56 andcontrols the flow of fluid under pressure from the high pressure passage55 outwardly through a discharge passage 59 into a, sump s formed in thevalve box 56a and which communicates with and forms a part of the mainsump 43 (Figures 2 and 3). A U- shaped passage 63 extends from the lowerend of the valve bore 56 downwardly past a valve controlled port 64 andinto a passage 65, all formed in the casing of the valve box 50a. Thepassage 65 opens at its forward end into communication with a passage 66(Figure 1) formed in the body of the housing l5 (Figure 2) andcommunicating with the passage 22 that leads to the cylinder 2|. Thevalve box 50b and associated passages and valve mechanism issubstantially the same as the valve box 50a just described. It will besufficient to note thatthe high pressure passage 49 (Fig ure 3) from thepump gears 46 leads through a conduit 49a into a high pressure passage55', outward flow of fluid-therefrom through a discharge passage 59' tothe sump s of the valve box 56b being controlled by a valve 51"operating in a valve bore 56. A high pressure passage 63' leads from thelower end of the valve bore 56' through a valve controlled port 64' andinto a high Dressure passage 65'. The latter passage communicates with apassage 66' (Figures 1 and 3) which conducts the fluid under pressureinto the passage l 34 that leads to the cylinder 3 I.

In theoperation of both of the valves 51' and 51', upward movement ofthe valve closes oil the flow through the discharge passage, 59 or 59',and fluid is caused to flow under pressure from the pump through thepassages or 55,-63 or 63, past the associated check valve and into thehigh pressure passage 65 or 65' leading to the associated ram unit 25 or26. Moving the vvalves downwardly from their neutral position, as shown,

55 serves to open the associated check valves and permits oil or otherfluid under pressure to flow from the respective ram units back into thesump 41. By virtue of this construction, moving either of the valves 51or 51' from its neutral position serves to cause the rockshaftassociated therewith,

l6 or 28 (Figures 2 and 3), to move in one direction or the other.Usually, the agricultural implement tools normally associated with therockshafts are so connected that they tend to move the rockshafts in onedirection, such as the lowering direction, while the hydraulic pressureacting against'the rockshafts through the above described pump units andram units serve to cause the rockshafts to rock in-the other direction,un- 70 der the control of the associated valve mechanism.

Coming now to the valve controlling structure with which the presentinvention is more particularly concerned, it will be seenfrom Figure 4that the valve 57 of the valve box 5011 is connected to be raised andlowered by an arm *ll connected to the valve 51 by link means 12 andfixed to a tubular shaft 13 disposed within the casing 14 of the valvebox 5011'. The tubular shaft 13 extends outwardly of the housing 14 atthe innerside thereof and has secured thereto, as by welding or thelike, anarm which at its lower end has a socket 11. Movement of the arm16 in one d1,

in a neutral position, as shown in Figure 4, lie in u the sockets "1-1and 91, whereby rocking movement of the'member III! in one directionorthe other,

in a plane perpendicular to the plane of the paper in Figure 4, servesto rock both of the arms 19 and 95 in one direction or'the other,thereby rectioif or the other from a neutral'position therefore movesthe valve 51 upwardly or downwardly from its neutral position, as shown.A second shaft 9| is disposed within the tubular shaft 13 and at itsinner end-has an arm 92 fixed thereto which, through suitable linkage,is connected tobe moved proportional to the movement of the rockshaftI9. One arm of the continuous control linkage just mentioned is shown inFigure 4' by the reference numeral 94 and the link that controls thepart 34 and is connected with the arm I1 on the rockshaft I9 isindicated in Figure 2 by the reference numeral 95. Thislinkage issimilar to the corresponding linkage shown in the aboveoperating bothvalves 31 and 51. The upper end of the member I I9 is threaded, as atH9, and -re-,

ceives the threaded section I2 I of a valve controlv handle I22. Thelower end of the threaded sec-f .tion I2I is extended laterally to forma flangel I23 that overlies both cam members 31 and I" when the memberII! is in a neutral'position, as

shown in Figure 4. When the member III, I22

isshifted, say to the right as viewed in Figure 4,

rocking movement of the valve handle I22 therefore serves to actuateonly the'valve 51, and sim- 1 ilarly, when the member I I5, I22 is movedto the mentioned Worthington patent. The inner shaft 91 extendsoutwardly of the casing 14 beyond the end of the tubular shaft 13 andhas a cammember 81 fixed thereto in any suitable manner.

Again referring to Figure 4, the other valve box 90b has operatingmechanism for the valve 51 which is substantially the same as that justdescribed. The upper end of'the valve 51' is connected by a link 9I toan arm-92 that is fixed to a tubular shaft 93.' axially from a secondtubular shaft 94 that extends outwardly ofthe casing'14 of the valve box50b at the laterally inner side thereof, and the outwardly extended endof the tubular shaft section 94 is provided with an arm 95 which ispreferably identical with the arm 16, having a lower socket 91, asshown. The two tubular shaft sections .93 and 94 are connected to berocked to- 1 gether by arms 99 and 99, connected together by a rod IOI.The tubular shafts 93 and 94 are mounted on a shaft I03 that extendsfrom one side .to the other of the casing 14' and at one point is 7provided with a continuous control linkage arm I04 which functionssubstantially in the same way as the arm 92 in the valve box 50a, thearm I04 being connected by suitable linkage I05 and, I09 (Figure 4' andFigure 3) with the arm 29' that is fixed to ,the' rockshaft 49 (Figure3). A cam I03, similar to the cam 81, is fixed to the end of the shaftI03 that extends outwardly orthe casing 14 laterally inwardly in axialalignment with the corresponding shaft 8Iv of the valve box 50a.

. One of the principal features of thepresent invention is the provisionof a control whereby the two-ram units and 26 may both be operated atthe same time, or either may be operated independently of the other,with one adjustment, effective for both ram units, for automaticallydetermining or adjusting, the point at which either or both of therockshafts I0 and 29 .will be hydraulically locked against furthermovement,

- thereby adjusting or determining an operating position for the tool ortools associated withthe rockshafts I9 and 28. To this end, a. valveactuating member H5 is mounted for rocking movement on theadjacent endsof the shafts M and I03 and is also capable of lateral sliding move-]ment in either direction from a neutral position,

as will be clear from Figure 4. The member H5 is extended downwardly, asat H6, and is provided with a cross bore carrying a transverse pin II1,the ends of which, when the member 0 is left, as viewed in Figure 4,only the valve 51' will.

be controlled. Specifically, in the first instance where the member II5, I22 is shifted to the right, the pin II1 is disengaged from thesocket 91 and the flange I23 is moved out of the path of movement of thecam member I03,and when the ,valve member 3,122 is moved totfie left,the flange I23 and the pin II1 move out of connection with the cam 31and the socket 11.

In operation, assuming first that the member IIIS, I22 is in a neutralposition, controlling both The latter shaft is spaced valves 51 and 51',when the'valve handle "I22 is moved forwardly, the pin III acts to swingboth of the arms 16 and 95 in a direction to raise both valves 01 and51. This causes fiuid from the two pumps to be directed into the two ramunits' 23 and 29, causing both pistons I9 and 32 to be moved rearwardly,thereby rocking both rockshafts I 9 and 28 in what may be termed theirraising direction. The operator may at any time terminate the movementof the rockshafts I9 and 29 in their raising direction by returning thevalve handle I22 to its neutral position. 'If he fails to do this,suitableend return linkage is providedfor automatically returning thevalves 51 and 51, and the associated member II5, to a neutral position.Such end return linkage, preferably similar to that shown in theWorthington patent, includes a part adapted to beengagedby the rear endof the connecting rod of each ram unit, such member being suitablyconnected by an arm to the associated tubular shaft, 13 or '93, such armbeing indicated in Figure 4 by thereference numerals I 29 and I29,respectively,ithe arm 99 forming a part of the arm I29 inthe valvebox'50b. 0

When the tools or other implement units cofinected'with the rockshaftsI3 and 29 are in their raised or corresponding position, they may bemoved out of that position by moving the valve handle- I22 rearwardly,the latter still occupying its centralcr intermediate position, as shownin Figure '4. The rearward movement of the1,valve handle I22 actsthrough the cross pin II'I to rock both shafts 13. and 93 in a directionto move the associated valves 51 and 51' downwardly. At their lowerends, these valves engage the stems of the associated check valves,opening the highpressure passages 05 and 95' and permitting fluid toflow from the respective ram 'units backto the sump 41. As the fluid isthus exhausted from the cylinders 2| and II, the pistons therein moveforwardly, accommodating the corresponding rocking movement of therockshafts I3 and 23. As these parts rock in what may be termed theirlowering direction, the continuous control shafts 9| and I03 are alsorocked in a corresponding direction amount through theassociatedpontinuouscontrol linkage 84, 85 and I05, I06. This movementof the shafts 8| and I03 swings the cams "and I08 forwardly, eventuallyengaging the flange I23 on the valve handle I22. A slight additionalmovementthen serves to automatically return the handle I22 to a neutralposition, thereby restoring the valves 51 and 51' to their intermediateposition and locking a certain amount of fluid in each ram unit. Thepoint at which this movement of the continuous control linkage andassociated shafts 8I and I03 returns the valve handle 2 to its neutralposition may I be adjusted by turning the sleeve section I2I upwardly ordownwardly on the threaded section stantially'the same way when thevalve control lever I22 is shifted into either a left hand or a righthand position, except that in that event only one or theotherof thevalves, and hence only one or .the'other of the associated ram units, is

controlled. 'For insuring-a'positive and definite movement of the valvecontrolling lever I22,

.either in its neutral position or in either of its "The above describedaction takes place in subtwo shifted positions, I'provide a gate memberI secured to either or both of the valve boxes 50c and 50b and having afirst slot I3I defining the neutral position of the handle I22, byvirtue of a small lug or extension I33 carried on the member I I5 andlying in the slot 'I3I. Right and left hand slots I34 and I35 are alsoprovided in the-gate I30 to receive the lug I33 when the lever I2I, -i'sin or the other of its shifted positions, and movement of the lever fromone position to the-other is accommodated by a transverse slot I36A'modifled-form'of the invention is shown in Figures 5 et seq. Referringfirst to Figure 5, this form of the invention includes a main hydraulic.

power lift unit I50 adapted to operate a pair of implement controllingmembers suitably connected with a tool or tools, such as cultivatorsorgthelike, whereby the tool or tools may be raised orloweredsimultaneously or independently; This mechanism is similar to themechanism shown in my prior U.- S. Patent 2,337,638, issued. December28,1943. Inthis form of the invention the hydraulic unit I58 issubstantially identical with the hydraulic'unit disclosed and claimed inthe above-mentioned Worthington patent; It will therefore be unnecessaryto completelyi describe the unit I50 except to say that a gear pump I5Iserves as a source of fluid under pressure for delivering oil undercontrol of suitposition of adjustment of the member I95 on the Idesired.- At the left side of the tractor, indicated by the referencenumeral Ia, an arm I59 is fixed byany suitable means to the left end ofthe rockshaft 'l55, and at the other end of the latter, a'

bell crank iBI is mounted for rocking movement,

preferably on a journal or bushing I 62 which provides for movement ofthe bell crank I6I relative tothe rockshaft I55. The bell crank I6I isheld in position between the outer end of the. right lateral extensionI51 and a collar I63 fixed to the rockshaft I55. Connected to the leftarm I59 is a cultivator lift pipe I65, and the arm I59 may have arearward extension I66 to which rear rigs may be connected. The bellcrank I6I at the other side of the tractor is also connected to acultivator push pipe I61, and likewise the bell crank I6I is providedwith a rearward extension "I to which other rear rigs may be connectedif desired, the extension "I forming a part of the rearwardly extendingarm I12 that includes a bifurcated portion I13 which is apertured toreceive a pivot pin I14. An auxiliary ram unit I16 is anchored at itslower end to a bracket connected to or carried by the tractor Ia, andthe movable piston unit I11 of the ram unit I16, is connected by a linkor strut I18 to the pivot I14. Fluid flows to the ram unit I16 through aflexible hose connection I8I connected into the valve box I 82 thatforms a part of the hydraulic unit I50.

The valve mechanism enclosed in the casing I82 and the operating andcontrolling rneans therefor is, in this form of the invention, quitesimilar to the valve means shown in Figure 4 and described above and thevalve mechanism. shown in the above-mentioned Worthington patent. It istherefore suflicient to note that, in this form of the invention, thehydraulic unit I50 incorporates means that causes fluid to be directedunder pressure into-the cylinder in which the piston controlling therockshaft I55 is movable, such valve mechanism also incorporatingsimilar means controlling the fiow' of fluid to and from the auxiliaryram unit I16. As best shown in Figure 5, the first mentioned controlmeans includes a hand lever I 85 having its lower section inscrew-threaded engagement with the upper end of an arm I86 that isconnected directly to and forms a part of the valve mechanismcontrolling the ram unit that rocks the rockshaft I55. A return cam I81is fixed to a shaft carried by the casing I82 and. is operativelyconnected with the piston associated with the rockshaft I55 so as to bemoved in a-forward direction so as to engage a flange I89 formed on thehand'lever I85 and return the latter to a neutral position when thepiston reaches a given point in its forward movement, depending upon theadjustment of the member I85 on the member I86. The hand lever forcontrolling the auxiliary ram unit I16 is indicated in Figure 5 by thereference numeral I and includes a lower section that is threaded ontoan arm I96 that is connected directly with the valve mechanismcontrolling the flow of fluid to and from the ram I16. A return cam I98is formed on a rockable member I99 that is connected by-a link 20I withthe piston section I18 of the ram I16, whereby when the valve is in a,position permitting fluid to flow from the ram back to the sump, theresulting movement of the piston section causes the member I99 to rockin a direction to carry the cam I98 into engagement with the lower endof the hand lever (I95 and to return the latter to a neutral position ata point in the cycle of operation which depends upon the threaded armI98. The particular valve mechanism incorporated in the hydraulic unitI58 is' invention except in combination with other novel v features.

The valve operating" handle I85 and the member I88 on which it ismounted are disposed for lateral movement toward and away from thecasing I82 while maintaining operative connection with the valvemechanism in the casing I82, and the flange I89 is of suflicient radialextent so that in any position of the member I85, I88 the cam I81 isadapted to enga e the flange I89 and restore the valve handle I85 to itsneutral position,

as described above. A connecting member. indicated in its entirety bythe reference numeral 2 III, is mounted for sliding and rocking movementon the casing I82, the latter having one or more aperrured lugs inwhichthe central part of the member 2I 8 is preferably disposed. Theleft end of the member 2I0 has a grooved section 2I2 which meshes with apinion 2I3 disposed on the disposed about the lower portion of the valvehandle I85 in a fairly snug fitting relation but with sumcient loosenessthat the rocking movement of the valve handle I85, in a fore and aftdirection causes the member 2III to'rock about its axis of support inthe lug M I. At the other endof the member 2I8 a forked section 2I9 isdisposed and has arms 22I adapted to embrace the other valve operatinghandle I95. The member 2I0 is mounted for sliding movement in a.lateraldirection from a position in which the arms 22I clear the valve handleI 95 into a position in which the latter valve is operated whenever themember M8 is rocked about its axis of support On the casing I82. Themember 2III is' shifted laterally by the lateralshifting movement of thevalve operatingmember I85, I86. and whenever the member 2IIl is shiftedthe pinion 2 I 8 and the valve stem 2 is rotated, and this action isutilized according to the present invention to secure a readjustment ofthe hydraulic system to provide for operating the two ram units overtheir full stroke in substangases the flange I89 and returns the valvehandle I85, and the associated valve mechanism, to a neutral orintermediate position. The parts are so arranged that when the rockshaftI reaches a given point in the lowering direction, depending on theadjustment of the handle I85 on the arm I88, the cam member I81 actsagainst the flange I89 and thearm I85 andraises the valve 252 to itsneutral position, thus automatically terminating the lowering movementof the rockshaft I55 and associated tools.

-'I'he other valve-252a is controlled by the valve handle I95 andtheassociated arm I98 and. in general, operates in the same way asdescribed above inconnection with the valve 252,.namely,

either to direct fluid under pressure through passages 254a and 212 tothe flexible hose I8'I leading to the auxiliary ram unit I18. or topermit fluid to flow from-the latter unit back to the sump S. Actingthrough the link 2III, when the valve 252a is lowered'to'permit fluid toflow from the ram unit I18, the resulting movement of the piston elementI18jand the link 20I causes the cam I98 to approach the lower end of thevalve handle I95, thus serving to automatically return the valve 252a toaneutral position whenever the piston of the ram unit I16 moves to apredetermined position, depending upon the adjustment of the member I95on the member I95.

It wasdescribed above how the left valve operating handle I85 may beshifted laterally into a position to disengage the section 2I9 of thelaterally shiftable member 2 I0 from the valve operating handle I95. Inthis position of the parts, either of the valves 252 and 252a may beoperated separately, as may be 1 desired. For, example, where right andleft hand cultivator rigs are con-' .nected with the arm I59 and I6I,the outfit may be employed for cultivating point rows, one valveoperating handle being used to raise the tools at one. side whilepermitting the outfit to travel a further distance before operating theother valve handle to raise the'tools at the other side.

tially the same time that either may be operated singly.

The valve mechanism incorporated in the unit I58 is showndiagrammatically in Figure '7 and, as.

mentioned above, is of substantially the same construction as is shownand claimed in the Worthington patent, identified above. Referring nowto Figure '1, rocking the handle I85 in the direction.

indicated F in Figure 5 (forward), raises a valve 252 and closes off anidle passage 253 leading to a sumpS and diverts oil under pressurethrough a passage 254 past a check valve 258 and out into a passage 259to the tram unit that rocks the rockshaft I55. Rocking the handle I 85in the other direction R (rearwardly) causes thelower end of the valve252 toopen the check valve 258, permitting oil to flow out of thera'munit-associated ,in a direction to swing the arm I59 rearwardly,

thus lowering the tools associated therewith. A link 2581s connected tobe shifted whenever the rockshaft I55 rocks in a rearward direction andthis, in turn, rocks the return cam member I81 (Figures 5 and 7) which,as described above, en-

It may also be desirable to raise and lower the tools at the same time,and according to the present invention this may be done easily andconveniently merely by shifting the valve handle I85 to the right, whichacts through the shiftable .member 2I0 to move the section '2!!! intoengagement with the othervalve handle I95. Then by rocking either valvehandle I85 or I forwardly, both valves 252 and 252a will be placed in aposition to raise the tools at both sides of the tractor at the sametime, and swinging either valve handle 18-5 or I95 rearwardly'willtherefore actupower would result in operation at approximately twice thetime "that would occur when either of the ram units is operatedindependently, for the reason that'the simultaneousioperation of bothunits require twice asvmuch oil as the separate operation of one unit.According to thepresent invention, I provide means whereby the lengthoftime required to operate either ram unit is substantially the same asthe length of time required to operateboth together. Briefly, thepresent invention contemplates installing a bleeder valve in the highpressure line and'to control the open and closed position of the bleedervalve 11-. by the shifting movement of the member 210 so that an amountof oil is diverted from the system or the other of said arms and awayfromfsaid other. or said one arm, respectively, movement of when onlyone ram unit. is operated, but whenboth ram units are operatedsimultaneously the bleeder valve is closed so as to utilize'the fullca'- pacity of the pump to raise both units.

As best shown, in Figure "l, the upper end of the bleeder valve stem2l4'is threaded, the threads being fairly coarse and the correspondingportion of the casingreceiving the valve stem! being correspondinglythreaded. The lower end of the stem 2" is formed as a needle valve,as'indlcated at 230 and cooperates with a bleeder opening 231 formed inthe passage 232 leading from the pump:

to the high pressure passage 253. Thus, whenever the member 2l0 isshifted in one direction or the other, the valve s'tem 2 is raised --orlowered,- The I capacity of the bleed is such that when the valveopening or closing the bleed passage 23L is open, sufllcient oil isdiverted so that one ram unit may be operated through its full stroke inapproximately the same time that both ram units are operated when thevalve is closed. To adjust the bleeder valve. the pinion 2l3 may beraised on the splined unper end of the stem 2| 4 and out of mesh withthe grooved section M2 to permit turning the pinion to a new position ofadlustment before remounting it on the upper end of the stem 2".

While I have shown and described above the each of said arms controllingthe associated valve means, and means on .said shiftable member adaptedto engage the notches of both of said arms when said shiftable memberis-in a central -position,'and the notch of one or the other of saidarms when said shiftable member is in one or the other of its lateralpositions, for operating onlyone or theother of said valve meansandhence ,only on or the other ofthe associated ram units.

3. A power lift device for agricultural tractors and the like,comprising a'pair of ramumts normally separately operable, each havingcontrolling valve means therefor,- said two controlling ---v alve meansbeing mounted in juxtaposition and each including a casing and a pair ofparts, each preferred structure in which the principles of the presentinvention have been incorporated. it is to be understood that myinvention is not to be limited to the particular detailsshownand'described above, but that,- in fact, widely different means maybe employed in the practice of the broader aspects of my invention.,What I- claim, therefore, and desire to secure by Letters Patent is:

l. A power lift device for agricultural tractors and the like,comprising a pair of ram units normally separately operable, each havingcontrolling valve means therefor, said two valve means being mounted injuxtaposition and each including a casing and a pair of parts, each pairof parts extending from the casing generally toward the other pair, andmeans mounted for sliding movement on one part of each pair ofparts andmovable from a position generally centrally of the other parts of saidpairs of parts selectively to a position ateither one side or the otherof said generally central position, said slidable means in its generallycentral position being operatively e'ng'ageable withboth of said otherparts of said pairs of parts for operating both of said valve meanssimultaneously so as to operate both of said ram units simultaneously,said slidablemeans in either of its other positions being engageablewith one pair of parts comprising an outer tubular shaft and an innercentral shaft extending outwardly from the end of said tubularshaft,.with the inner shafts extendingtoward one another, arms on 'theends of said tubular shafts, and a member shiftably mounted on theextended ends of said inner shafts and shiftable from a generallycentralposition engaging both of said arms to either one or the other of twolateral positions engaging one or the other only of said arms, saidvalve means being respectively operable by movement of said arms.

4. Control mechanism for power actuated apparatus including twojuxtaposed members and two follow-up mechanisms, each comprising a partoperatively connected with the associated juxtaposed member, saidcontrol mechanism comprising amember mounted for movement from anintermediate position generally centrally or the other only of saidother parts so as to operate one or the other only of said valve meansand one or the other only of said ram units associated therewith.

2. A power lift device for agricultural tractors and the like,comprisinga pair of ram units n'ormally separately operable, each having controlling valve means therefor, said two controlling valve means beingmounted in juxtaposition and each including a casing and a pairo'f-parts extending therefrom, one part of each pair comprising a shaftand the other part comprising an arm havinga notchand movable about theaxis of said shaft, a shiftable member slidably mounted on the adjacentends of said shaft'parts and shiftable thereon from a position generallycentrally between said arms into a position adjacent one justing theposition of said last mentionedmeans on said movable member whereby withone adjustment the point of operation of both of said juxtaposed membersmay be determined.

5. Control mechanism for a hydraulic unit comprising a pair of housingsdisposed in side by side relation, each having a pair of concentricshaftsextending outwardly of the housings from the adjacent wallsthereof, the inner shaft of each pair extending outwardly beyond theouter shaft, an operating arm on the end of-each outer shaft,

' a control arm on each inner shaft adjacent the associated operatingarm, and a control lever mounted for rocking movement on the adjacentends of said inner shafts and having parts engageable with said controland operating arms.

6. Control mechanism for a hydraulic unit comprising a pair of housingsdisposed in side by side relation','each having a pair of concentricshafts extending outwardly of the housings from the adjacent wallsthereof, the inner shaft of each 7 pair extending outwardly beyond theouter shaft,

an operating arm on the end of each outer'shaft,

a control arm on each inner shaft adjacent the associated operating arm,a control lever mounted for rocking movement about the axes of saidinner shafts, means on the control lever optionally engageable with saidoperating arms, and a part adjustable on said lever and optionallyengageable by said control arms.

, 13 7. A power lift device for agricultural tractors and the like,comprising' a pair of ram units nor-' mally separately operable, eachhavingcontrolling valve means therefor, said two controlling valve meansbeing mounted 'in juxtapositioned and each including a casing and a pairoi. parts, each pair of parts extending from the associated casingtoward the other pair, a shiftable member mounted on one part of eachpair of juxtaposed .parts and shiftable thereon from a position engagingthe other parts of said pairs of parts for operating both of said valvemeans and both of said ram units simultaneously optionally to either oftwo positions engaging only one or the other of said other parts, butnot both, for operating only one or the other of said valve means, areturn linkage operatively connected between each ram unit andthegassociated valve part on which said shiftable member is mounted, andmeans on each 01' said last mentioned valve parts outside the associatedcasing adapted to act against said shittable member for returning it toa neutral position.

THEOPHILUS BROWN.

auasva REFERENCES crran The following references are of record in thefile of this patent:

/ UNITED STATES PATENTS Number Date Name v 2,265,260 Argo Dec. 9, 19411,911,737 Allen May 30, 1933 842,961 Kewley Feb. 5, 1907 2,107,760McCormick Feb. 8, 1938 2,114,157 Towson Apr. 12, 1938 2,337,637 BrownDec. 28, 1943 2,103,530 Henry Dec. 28, 1937 2,331,790 Nichols Oct. 12,1943 2,311,516 Brown et al Feb. 16, 1943 2,347,368 Rosen Apr. 25,1944 v2,336,955 Ott Dec. 14, 1933 2,221,813 Paulsen Nov. 19, 1940 2,403,422Worthington July 2,- 1946 1,271,595 Matz July 9, 1918 FOREIGN PATENTSNumber Country Date 308,099 German Sept. 30, 1918

